Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers).
Input devices may employ transcapacitance (or “mutual capacitance”) to determine a change in capacitive coupling relating to the presence of an input object in a sensing region. In such cases, when the grounding condition of the input device is low or otherwise non-optimal (e.g., when the input device is lying on a desk, rather than being held by a user), certain parasitic capacitance effects may result in signal artifacts and/or produce other deleterious results. In general, this may referred to as a “low ground mass” condition.
Accordingly, there is a need for improved sensor systems and methods capable of addressing issues related to low ground mass conditions.